Morphological and histochemical changes occurring in mammalian lenses during development of hereditary, senile and drug-induced cataracts are to be studied. The histochemical experiments are aimed at further explocation of transport and digestive properties of the lens, including Na/K-ATP-ase and acid phosphatase location, and protein uptake. In addition, the location of protein sulfhydryls and disulfides, calcium, and capsular substances will be investigated. Laboratory animals involved in these investigations will be rats. Surgically removed human cataractous lenses will also be utilized. Ophthalmoscopic and slit lamp examinations will precede utilization of lenses for light microscopy and electron microscopy. It is anticipated that this research will yield further information concerning cataractogenesis in laboratory animals and in man.